Addition of E64 restores Δsrv in vitro biofilm formation to wild-type levels.

E64 (100 µM) was added to each well at the time of seeding of wild-type and Δsrv RGAS053, MGAS315, and MGAS5005 24 h biofilms. E64 restored biofilm formation of all Δsrv strains to wild-type levels. RGAS053 biofilm formation was increased compared to untreated RGAS053. Each reported value for the CV assay is an average of 6 replicates and is adjusted by the dilution factor required to obtain a spectrophometric reading (OD_{600 nm}) (*p≤.01, **p≤0.001, ***p≤.0001; unpaired t-test).